Some critical observations about the degradation of glass: The formation of lamellae explained

Non-destructive 3D exploration of silicate glass corrosion: a combined multiscale approach from the macro to the nanoscale

“…Examples of altered silicate glass, as reported in the literature, indicate that the multi-layer patina on the surface consists of a random arrangement of amorphous silica nanoparticles (NPs) with a varying level of packing density. 13,16,17 The initial surface state of the glass significantly influences the formation of the alteration layer. 29 Additionally, other than silica, crystalline and amorphous phases are frequently detected in the spaces between silica-rich layers.…”

“…40 While it was previously believed that the appearance of laminated layers was solely due to seasonal variations in formation conditions, 41 subsequent studies have demonstrated that glass corroded under steady laboratory conditions can develop a discrete lamellar structure similar to naturally aged glass. 16,42,43 The formation of this layered pattern has been associated to fluctuationtriggered organisational processes involving the dynamics between species in each alteration step. Some research has also drawn comparison between the layered structure of altered glass zones to those of Liesegang bands, 44,45 which arise from periodic precipitation phenomena of diffusion and reaction processes occurring in the wake of a moving reaction front.…”

“…[10][11][12][13][14] This lamellar structure is explained as the trace left behind by the advancing alteration front, propagating from the surface towards the inner bulk areas of unaltered glass. 15,16 Experiments aimed at reproducing the lamellar multi-layer structure of altered glass 15,17 have provided significant evidence for this model, especially in nuclear waste glass studies. However, defining conditions to model the mechanism of lamellar multi-layer formation within experiments of realistic duration remains a challenge.…”

Combined MA-XRF, MA-XRPD and SEM-EDX analysis of a medieval stained-glass panel formerly from Notre Dame, Paris reveals its material history

“…[42][43][44] A detailed description of glass degradation mechanisms and the structural changes inside the glass it may cause can be found elsewhere. 45 The most commonly found corrosion crusts on medieval stained glass include the sulphates gypsum (CaSO4•2H2O) and syngenite (K₂Ca(SO₄)₂•H₂O). When looking at Figure 3H, it becomes apparent that the S-distribution is very similar to the shape of the crust, suggesting that one or more sulfate salts precipitated on the surface of glass window.…”

Photonic crystals built by time in ancient Roman glass

“…Generally, the corrosion patinas found on glass are formed by slow degradation of the bulk materials through proton leaching (replacement of alkali metal ions with protons from the water the glass is in contact with) ( 15 ) and silica dissolution and reprecipitation into nanoparticles ( 16 – 18 ). These pH-dependent transformations induce a restructuring of glass into nano- to micrometer-thick lamellae formed by nanoparticles with regularly alternating packing density, which give ancient glass its characteristic iridescent patina.…”